Ain’t Jokin
Does "Ain’t Jokin" in the following context mean "I am not joking" or "there is no joke (it is not a jock but is very serious)?
Context:
"Ain’t Jokin’ is one of Carrie Mae Weems’ earliest photographic series, and established the wry wit, intimate portraiture, and interplay with text for which she is well known. The images in this series are titled after supposedly humorous stereotypes about black culture, which contrast mightily with the portraits themselves. For example: “Black Man Holding Watermelon.”